thoracic viscera, it is not always possible to determine whether it has penetrated the chest wall; although the direction and situation of the wound, and an account of the way in which it was inflicted may point to its having done so. Under these cir

cumstances, the wound should on no account be probed, but the patient treated as if the wound had penetrated, and watched for signs of inflammatory complications. The symptoms and treatment will depend upon the viscus wounded (see Wounds of Thoracic Viscera).

Injuries of the Contents of the Chest.

These may be divided into injuries of the-1, pleura and lung; 2, pericardium and heart; and, 3, large blood-vessels.

1. INJURIES OF THE PLEURA AND LUNG.-Contusion of the lung without an external wound may be produced by a severe crush of or blow upon the chest. The visceral layer of the pleura may or may not be lacerated. It is attended by paroxysmal dyspnoea, cough, localized dullness, and crepitation, followed in a few days by expectoration of rusty sputa. If the visceral layer of the pleura is lacerated, blood or air may escape into the pleural cavity, and there will then be, in addition to the above, signs of hæmo-pneumothorax. The patient usually recovers in a few days, but pneumonia, pleurisy, or abscess or gangrene of the lung occasionally ensue.

Wounds of the pleura and lung may be produced by the fragments of a broken rib, or by a stab or gunshot. When attended by a penetrating wound of the chest, they are very serious. The pleura alone may be wounded, but more often the lung is injured at the same time. Signs.-No single symptom is sufficient to make it certain that the lung has been wounded; but where several of the following are present, the diagnosis becomes fairly certain. Thus, there may be severe shock, abdominal breathing, and cough with expectoration of frothy, blood-stained mucus, or even of pure blood. If there is an external wound, there will be escape of air intimately mixed with blood, and accompanied by a peculiar hissing noise (hæmatopnea); or if there is no external wound, emphysema in the region of the fractured rib. When the pleura alone is injured, a very rare accident, the signs are similar; but no blood is coughed up, and though air may escape from the external wound, if there be one, it is not churned up into a fine froth with the blood, as in this case it does not escape from the lung, but is simply drawn in and out of the pleura through the wound in the parietes during inspiration and expiration. Complications.-Hemothorax, pneumothorax, emphysema, hemorrhage, and, later, pleurisy and pneu

monia (see Complications of Injuries of Chest). Treatment.Absolute rest, with such treatment as is appropriate for the serious complications that may be present. If the pleura alone is injured, the external wound should be closed, unless any complication exists, and dressed antiseptically.

2. INJURIES OF THE HEART AND PERICARDIUM.-Contusions, wounds, and rupture of the pericardium may at times be produced by a severe crush of the chest walls; but are more often due to the penetration of a fragment of a broken rib, or to a stab, or gunshot. In the last two instances the heart is generally also involved. Signs.-Severe shock, hemorrhage, the position and direction of the wound, and subsequently symptoms of pericarditis. The prognosis is always very serious, death either occurring from the effused blood impeding the heart's action, or from pericarditis. The treatment consists in absolute rest, the local application of cold and, if inflammation threatens, of leeches. Should the heart's action become seriously impeded by effused blood, serum, or pus, aspiration or free incision and drainage may be required. When there is an external wound, it should be dressed antiseptically.

Wounds of the heart, especially when they penetrate one of its cavities and involve an auricle, are generally instantaneously fatal from shock or hemorrhage. Remarkable exceptions, however, occur, and patients have been known to linger for a few hours or a few days, or even to recover. Signs. When not at once fatal, a wound of the heart is attended by great collapse, syncope, a fluttering pulse, and dyspnoea, and, later, by symptoms of pericarditis. The treatment is the same as that for a wound of the pericardium.

Rupture of the heart, though rare, occasionally occurs as the result of great external violence to the chest walls, or of some sudden exertion on the part of a patient with disease of the heart's substance. Death is, as a rule, almost instantaneous.

3. WOUNDS OF THE LARGE BLOOD-VESSELS, as the aorta or vena cava, are almost invariably and immediately fatal, and require no further comment here.

Complications of Injuries of the Chest.

The chief complications attending injuries of the chest are: 1, external hemorrhage; 2, hæmothorax; 3, emphysema; 4, pneumothorax; 5, prolapse and hernia of the lung; 6, pleurisy; 7, pneumonia; 8, hæmopericardium; 9, pericarditis; 10, mediastinal abscess.

1. EXTERNAL HEMORRHAGE in penetrating wounds of the chest walls may come from: (1), an intercostal artery; (2),

the internal mammary artery; (3), a wound of the lung; or (4), a wound of the heart and one of the large vessels. Hemorrhage from an intercostal or the internal mammary artery, though it may generally be known by the blood escaping in jets, is sometimes difficult to distinguish from hemorrhage from the lung. In such a case it is said that if a card be introduced into the wound, the blood, if it comes from an artery in the chest wall, will flow over the outer surface of the card, but if it comes from the lung will well up around the card. Hemorrhage from the heart or one of the large vessels is, as a rule, immediately fatal. Treatment.-1. An intercostal artery should, if possible, be tied; otherwise a pressure forceps may be left on, or the artery with the periosteum may be separated from the lower half of the rib and then tied, or a portion of the rib may be excised. 2. The internal mammary, in the four upper spaces, can be easily tied; in the lower spaces a portion of the costal cartilage must be first cut away. 3. When the bleeding is from the lung the patient must be placed at perfect rest on the injured side, and an ice-bag applied. Internally, lead and opium, gallic acid, or ergot, may be given. Some recommend the closing of the external wound and the application of a bandage to the chest, so that the blood may collect in the pleura, press on the lung, and thus stop the bleeding.

2. HÆMOTHORAX, or hemorrhage into the pleura, may occur either with or without an external wound. It is, perhaps, most often due to a fragment of a broken rib penetrating the lung or wounding an intercostal artery. The signs are those of internal hemorrhage with rapidly extending dullness to percussion, absence of breathing sounds, bulging of the intercostal spaces, and increasing dyspnoea. It may be distinguished from pleurisy and pneumonia by coming on immediately after the injury and by the absence of fever. Treatment. Similar to that for hemorrhage from a wounded lung. Should the breathing become dangerously embarrassed the blood must be drawn off by the aspirator. Should suppuration occur the chest must be opened and freely drained.

3. PNEUMOTHORAX, or air in the pleura, is generally the result of a wound of the lung by a fragment of a broken rib. It may be known by increased resonance to percussion, amphoric breathing, metallic tinkling, bulging of the intercostal spaces, and increasing dyspnoea. When combined with hæmothorax or with pleuritic effusion, the lower part of the chest will be dull to percussion, and a splashing sound on shaking the patient (succussion) may be heard on auscultation. The air is usually absorbed, but should the breathing become seriously affected it may be removed with the aspirator.

4. EMPHYSEMA, or surgical emphysema as it is sometimes called to distinguish it from the medical affection of the same name in which the air-cells of the lung are dilated, is air in the connective-tissue spaces. It is generally due to a wound of the lung combined with a laceration of the parietal and visceral layers of the pleura, and is a very frequent complication of fractured ribs. The air either escapes into the pleura at each inspiration, and thence during expiration is forced through the parietal layer into the subcutaneous connective tissue, or passes, if there are adhesions between the two layers of the pleura, directly from the lung into the subcutaneous tissue. Rarely it is due to a rupture of the lung without injury of the pleura, the air then escaping at the root of the lung into the posterior mediastinum, and thence into the connective tissue of the neck and arms. More rarely still it may occur without a wound of the lung, or even without a wound of the pleura. Signs.-The emphysema, though usually limited to the seat of injury, may extend somewhat widely around it, and in rare instances has spread over the whole body. It gives rise to an ill-defined flattened swelling unattended by signs of inflammation and unaltered on inspiration and expiration. On pressing on the swelling a peculiar crackling sensation is experienced, like that of rubbing the hair between the fingers. Treatment.—A pad and bandage are all that is usually necessary, but should the air instead of becoming absorbed extend so widely as to interfere with respiration, a puncture or two must be made to let it escape.

PROLAPSE AND HERNIA OF THE LUNG.-Prolapse of the lung occasionally occurs. It should be returned by gentle pressure, the wound being slightly enlarged, if necessary. If the prolapsed portion has become adherent and congested it may be removed by the knife or ligature, taking care not to open the pleura. Hernia of the lung is sometimes met with after a penetrating wound of the chest has cicatrized, or even when there has been no wound of the skin. It forms a soft, crepitating, resonant swelling, which can be made smaller by pressure and generally becomes more prominent on forced expiration or coughing. On listening over it a harsh, vesicular murmur is heard. The treatment consists in protecting it with a properly shaped pad or leather shield moulded to the part.

For an account of such complications as Pleurisy, Pneumonia, Hæmopericardium, Pericarditis, and Mediastinal Abscess, a larger work, or one on Medicine, must be consulted.

OPERATIONS ON THE CHEST.-Tapping the pleura should be done when the effusion is serous without admitting air, either by the aspirator or by the syphon-trochar and cannula. The spot

usually selected is the sixth intercostal space in the mid-axillary line. A small incision is first made through the skin, which should be drawn down on the rib, so that the wound may be valvular. The needle of the aspirator or the trochar and cannula is then thrust into the pleural cavity. The fluid should be allowed to escape slowly, and its flow stopped for a minute or so if coughing occurs. The instrument must be withdrawn should any blood become mixed with the fluid. The wound should be dusted with iodoform and closed with a pad of antiseptic gauze. Incision and drainage of the pleura may be required for empyema, the removal of putrid clots, etc. The incision may be made in the sixth intercostal space in the mid-axillary line, or in the ninth, tenth, or even eleventh space in a line with the angle of the scapula. Chloroform should always be given, and a careful dissection made between the ribs down to the pleura. The pleural cavity should then be opened and a drainage-tube inserted. If the space between the ribs is insufficient, a piece of a rib may be excised. The wound should be treated antiseptically, and if pus again collects a counter-opening may be made.

Tapping the Pericardium.-The puncture should be made with the aspirator in the fourth or fifth intercostal space on the left side about two inches from the sternum. Care should be taken not to injure the internal mammary or an intercostal artery, and not to thrust the needle too deep, lest the heart be punctured.

Incision and drainage of the pericardium may be required for pus in its cavity. An incision about two inches long should be made along the upper border of the fifth or sixth rib, beginning one inch from the sternum. When the pericardium is reached it should be freely opened, a drainage-tube inserted, and antiseptic dressings applied.

Pneumotomy, or incising the lung for the purpose of opening an abscess or hydatid cyst, or of draining a phthisical or bronchiectatic cavity, has in a few instances been done. An incision is made down to the pleura, a trochar and cannula then thrust into the cavity in the lung, and the wound made by the cannula cautiously enlarged by dressing forceps.

INJURIES OF THE ABDOMEN.

CONTUSIONS of the abdominal wall, especially when due to a sharp or sudden blow, or a severe crush, should always be regarded as serious, as they may be complicated with grave internal injuries. Thus the peritoneum may be lacerated, one of the viscera ruptured, or a large blood-vessel injured and blood extravasated into the peritoneum or subperitoneal tissue; while among